The clinical manifestations of chronic pyelonephritis are more complicated, and common manifestations include different degrees of low-grade fever, intermittent urinary frequency, urinary discomfort, lumbar pain and impaired renal tubular function. Chronic pyelonephritis refers to inflammation of the renal pelvis and renal parenchyma, and belongs to a type of upper urinary tract infection, which is mostly caused by bacterial infection, often accompanied by inflammation of the lower urinary tract. Its clinical manifestations are more complex, systemic and localized urinary manifestations are atypical, sometimes only manifested as asymptomatic bacteriuria. More than half of the patients may have a history of acute pyelonephritis, followed by varying degrees of low-grade fever, intermittent urinary frequency, urinary discomfort, lumbar pain, and impaired renal tubular function, such as nocturia, hypogranulonephrosis, etc. The disease may progress to chronic nephritis. Persistent disease can develop into chronic renal failure. If patients find chronic pyelonephritis, it is recommended to go to the regular hospital in time, under the guidance of doctors to standardize the treatment.